The present invention is directed to a three-output level logic circuit and more particularly to a circuit in which the third logic level has no affect on a driven circuit.
In a computer or calculator it is desired to common the outputs of several switching components onto a single data line. This reduces the necessary hardwire connections.
Normally, however, the common line is unduly loaded by the components and therefore the number of components must be limited. Where coupling units are used for isolating each component the switching speed of the computer is lowered; this is partially due to impedance mismatch problems relative to the positive and negative going edges of the logic pulses.